Capping coating for 3d integration applications

ABSTRACT

A structure for a semiconductor component is provided having a bi-layer capping coating integrated and built on supporting layer to be transferred. The bi-layer capping protects the layer to be transferred from possible degradation resulting from the attachment and removal processes of the carrier assembly used for layer transfer. A wafer-level layer transfer process using this structure is enabled to create three-dimensional integrated circuits.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/607,744 filed on Sep. 9, 2012, which is a divisional of U.S. patentapplication Ser. No. 12/192,367 filed Aug. 15, 2008, which is adivisional of U.S. patent application Ser. No. 10/645,047 filed Aug. 21,2003 which claims benefit of U.S. Provisional Application 60/444,502,filed Feb. 3, 2003, entitled “Silicon Nitride/A110 Capping Bi-Layer inCopper-Polyimide Systems for 3D Integration Applications”.

FIELD OF THE INVENTION

The present invention relates to the integration of circuit componentsinto a 3D structure using a wafer-level layer transfer process based onthe incorporation of capping bi-layers for reliable connection ofintegrated circuits, components, and other semiconductor components.

BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART

In recent years, a variety of three-dimensional (3D) integration andpackaging techniques have been examined. The main considerations behindthe use of 3D integration are: 1) minimization of the wire length, 2)incorporation of new back-end-of-the-line (BEOL) processes that arecurrently limited by conventional planar technology, and 3)implementation of related design flexibility. Items 1-3 mentioned abovewould allow significantly reduced interconnect delay as well as acomplex system integration to increase both performance andfunctionality.

Approaches to 3D integration at either the chip or wafer level have beendescribed in the prior art. For example, wafer level bonding can beachieved via an assembly approach. In such a method, layers aretransferred one by one, on top of each other, and attached by a bondingprocess. The prior art layer transfer process is realized using carrierwafers, most often a glass substrate.

In such a scheme, the glass substrate is attached to the structure by anadhesive bonding process and released after the layer transfer iscompleted. One of the methods to release glass is based on laserablation, which entails irradiating the glass/adhesive interface throughthe back surface of the glass substrate. In order to accomplish theablation process, polyimide materials are typically used as asacrificial adhesive layer in prior art 3D integration schemes. Thepolyimide sacrificial adhesive layers are deposited on top of the layerthat will be subsequently transferred. During ablation, the depositedenergy is contained within a shallow (submicron) surface layer for anapproximate 50 ns duration of the excimer laser pulse due to thepolyimides strong absorption properties of ultraviolet laser radiationand poor thermal conductivity. When the absorbed energy density exceedsa certain threshold value, a surface layer having a thickness of lessthan 1 μm is photo-ablated and the laser separation of the glass carriersubstrate is realized. The laser ablation process using polyimides hasbeen reported and a comprehensive summary has been provided bySrinivasan, et al., “Ultraviolet Laser Ablation of Organic Polymers”,Chem. Rev. 990, 1303-1316 (1989).

The assembly approach in which laser ablation is used is only one of theexamples in which the polyimide material is used in a 3D integrationscheme. In general, in 3D structures, the polyimide layer is depositedon an already processed and tested device layer terminated with at leastone Cu-based wiring layer. When a polyamic acid (PAA) solution, which isthe precursor for the formation of polyimide films, is spin applied tothe Cu surface and subsequently cured at a temperature between 350°-400°C., Cu reacts with the polyamic acid during the curing step to formsalts which diffuse into the polyimide layer to form copper oxideprecipitates. This is disclosed, for example, in Kim, et al., “Adhesionand Interface Investigation of Polyimides on Metals”, J. Adhesion Sci.Technol., Vol. 2, No. 2, pp. 95-105 (1988). As demonstrated byKowalczyk, et al., “Polyimide in Copper: The Role of Solvent in theFormation of Copper Precipitates”, Appl. Phys. Lett., Vol. 52, No. 5,pp. 375-376, (1988), the polyimide precursor solvent, n-methylpyrrolidone (NMP), provides mobility for the aggregation of Cuprecipitates.

This situation is worsened when photosensitive polyimides are used sincereacted Cu leaves a residue upon development, which is very difficult toclean; see, in this regard, Perfecto, et al. “Evaluation of Cu CappingAlternatives for Polyimide-Cu MCM-D”, ECT. '01 (2001). In the case of apreimidized polyimide, Cu diffusion has been observed and documented inU.S. Pat. No. 5,081,005. Over the years, the copper-polyimide interfacehas been well studied. Copper-polyimide technology has been successfullyused in the form of multi-level thin film structures for over twodecades now. It has been primarily developed for use in thecost/performance SCM's and high end MCM's applications; see, forexample, Prasad, et al., “Multilevel Thin Film Applications andProcesses for High and Systems”, IEEE Transactions and Components,Packaging, and Manufacturing Technology-Part B, Vol. 17, No. 1, pp.38-49 (1994).

In these applications, to prevent copper diffusion into the polyimide,various metal capping layers have been used. Illustrative examples ofprior art polyimide capping layers include, for example, Cr, Pt, Pd, Ti,Co(P), and chromate treatment; see, in this regard Matienzo, et al.,“Adhesion of Metal to Polyimides, in Polyimides: fundamentals andapplications”, K. K. Ghosh and K. L. Mittal Eds., Marcel Dekker, NY,N.Y. (1996); Shih, et al., “Cu passivation: a method of inhibitingcopper-polyamic acid interactions”, Appl. Phys. Lett., Vol. 59, No. 12,pp. 1424-1426 (1991); Ohuchi, et al., “Summary Abstract: Ti as adiffusion barrier between Cu and polyimide”, J. Vac. Sci. Technol. A,Vol. 6, No. 3, pp. 1004-1006 (1988); O'Sullivan, et al., “Electrolesslydeposited diffusion barriers for microelectronics”, IBM J. Res.Develop., Vol. 42, No. 5, pp. 607-619 (1998).

Also, baseline requirements for a capping layer in the Cu-polyimidesystem used for various packaging structures have been established.Namely, any Cu passivation metal should be chemically inert andinsoluble in PAA; and the passivation metal should be a good diffusionbarrier against Cu outdiffusion at temperatures less than 100° C. whenthe solvent NMP is present (above this temperature the Cu transportsinto the polyimide via solid-state-diffusion). Moreover, the passivationmetal should not diffuse into Cu to cause resistivity increase.

In addition to copper diffusion barrier properties, metal caps werefound to enhance adhesion between Cu and a polyimide. The shortcoming ofthis Cu/metal cap/polyimide is based on the processing limitation, forexample, when the metal wiring is defined by the subtractive etching ofa Cr/Cu/Cr sputtered film, Cr protection only occurs on the top of thewiring. Similar problems take place when a metal is deposited by alift-off process. Hence, this solution has been limited to patternelectroplated films, where Co or chromate treatments have been shown tosuccessfully encapsulate the Cu wiring.

However, in case of 3D integration applications, the concern about metalcapping layers is based on compatibility of these materials with variousheterogeneous structures involved in future 3D integration schemes. Thecapping could be introduced as a continuous layer across the wholewafer. In this case, after the layer transfer and ablation of the glasssubstrate is completed, this layer would be exposed to the removal ofthe polyimide (the removal step is not present in the aforementionedpackaging applications). Wet and dry methods have been used to removepolyimides, but oxygen-plasma based removal has been proven mosteffective, and it is also is a well understood process.

Therefore, in case of 3D structures, requirement of good Cu-diffusionbarrier (specially against activated oxygen in a plasma etchingenvironment) is additionally mandated of the capping layer. Sincetitanium is prone to oxidation in an oxygen-plasma, it cannot beconsidered as a candidate for a capping layer. Even if other cappingmetal candidates are stable in the oxygen-plasma environment, once thepolyimide stripping process has been completed, the additional step ofremoving the sacrificial capping layer would have to be implemented inorder to provide electrical separation between Cu wires. This removalprocess needs to be CMOS compatible, and preserve the structural,mechanical and electrical stability of the underlying patternedstructures. Selective etching of such capping metals without degrading(etching or damaging) the underlying copper wires makes the choice ofsuch a metal cap layer even more difficult. Taking all theserestrictions into consideration, the metal capping-sacrificial coatingof a full wafer is not likely to be feasible from the manufacturingpoint of view.

The metal capping in the form of a selective cap, such as electroless Coon the top of Cu structures, could be implemented in a 3D integrationscheme. However, application of such a cap will be limited, as 3Dstructures may implement various heterogeneous materials and theircompatibility with Co, or other relevant selective metal caps would haveto be established.

The organic copper-capping technology for the Cu-polyimide system wasalso developed for thin film packaging. It has been shown that a thinorganic coating, such as poly(arylene ether benzimidazole) (PAEBI),silane-modified polyvinylimidazole, or polybenzimidazole, can be applieddirectly to a wiring layer for enhancing adhesion to both the copperwiring and the polymer dielectric surface. These materials provide 100%protection for copper wiring, eliminating the need for metal capping,but at the expense of adding a thermal treatment step prior to thecoating of the polyimide. This is described, for example, in Lee, etal., “Adhesion of poly (arylene ether benzimidazole) to copper andpolyimides”, J. Adhesion Sci. Technol., Vol. 10, No. 9, pp. 807-821(1996); and Ishida, et al., “Modified Imidazoles: degradation inhibitorsand adhesion promoters for polyimide films on copper substrates”, J.Adhesion, Vol. 36, pp. 177-191 (1991). Such predominantly organic capswill be attacked by oxygen plasma exposure and will not protect thecopper wires during the post ablation cleaning step of plasma ashing.

Organic caps that do not require additional thermal treatments have beenevaluated by Perfecto, et al., “Evaluation of Cu capping alternativesfor cu-Cu MCM-D, ECTC” 01 (2001).

Two approaches were investigated in the Perfecto, et al. paper: 1)re-formulation of the PAA with an additive which will reduce the Cudiffusion and/or prevent Cu from complexing with the PAA, and 2) spundry precoat of a Cu surface with an organic solution that reacts with Cureducing the availability of Cu for diffusion. In the first method, 1%tetrazole in a polyimide solution, and 5% benzotriazole (BTA) in apolyimide solution were evaluated, while in the second method an aminosilane, namely, 3-aminopropyl-trimethoxy silane diluted to 1% indeionized water, as well as BTA diluted to 1% NMP were studied. Allsystems showed degraded performance when compared to the simplest andmost robust process of coating copper with 3-aminopropyl-trimethoxysilane. A layer of 3-aminopropyl-trimethoxy silane exhibited superiorperformance as an adhesion promoter in the Cu-polyimide system, and as aCu-diffusion limiting layer, and its use as a capping layer inpackage-related applications has been described in U.S. Pat. Nos.5,081,005 and 5,194,928.

However, a coating of 3-aminopropyl-trimethoxy silane (usually a fewmonolayers) is not stable in the plasma-environment, and hence it cannotserve as an oxygen-diffusion barrier. Therefore, its use as a cappinglayer in the 3D integration applications is limited to schemes when nooxygen-plasma processes are involved. However, other characteristics of3-aminopropyl-trimethoxy silane, such as its ability to promoteinterfacial strength in both polyimide/silicon dioxide andsilicon/silicon nitride laminates, make this system a great candidate inthe scheme for capping layer discussed below.

In view of the above, there is a need for providing an improved cappinglayer which provides adhesion as well as protection to underlying layerssuch as metal-based semiconductor elements.

SUMMARY OF THE INVENTION

The present invention relates to the three-dimensional integration ofsemiconductor elements, such as devices and interconnections, using anovel layer transfer process. Moreover, the present invention overcomesthe difficulties associated with the integration of various materialsand devices through the use of a passivation capping coating to protectthe underlying metal-based semiconductor elements. The inventive processprovides a wafer-level layer transfer that is compatible with CMOStechnology and enables integration of various active, passive andinterconnecting circuit elements.

In particular, it is an object of this invention to provide a supportingstructure for an integrated 3D interconnect circuit for high frequencyand high speed computing applications.

It is a further object of the present invention to combine the know-howof layer transfer technology to form a complete high densityinterconnect structure with integrated functional components.

It is a still further object of this invention to enable a low cost ofownership process based on a bi-layer capping coating using an adhesivecomponent and a diffusion barrier component.

Specifically, and in broad terms, the present invention provides astructure for interconnecting semiconductor components comprising:

a layered substrate including, for example, semiconductor components,for transferring;

a bi-layer capping coating on top of the substrate, each layer of saidcoating provides adhesion and protection; and

a carrier assembly.

The inventive structure can be used for interconnecting varioussemiconductor components including, for example, semiconductor devices,semiconductor circuits, thin film layers, passive and/or activeelements, interconnect elements, memory elements,micro-electro-mechanical elements, optical elements, optoelectronicelements, and photonic elements.

In addition to the above-mentioned structure, the present invention alsoprovides a method for fabricating the same. Specifically, and in broadterms, the method of the present invention comprises the steps of:

providing a layered substrate for transferring;

forming a bi-layer capping coating on the substrate, each layer ofcoating providing protection and adhesion; and

forming a carrier assembly on the bi-layer capping coating.

The bilayer capping coating of the present invention is formed bydepositing at least two consecutive layers, hence creating a bi-layerprotecting the substrate to be transferred from negative effects ofattachment and the later removal of the carrier assembly.

The present invention also provides a method for wafer-level transferthat comprises the steps of:

providing a layer to be transferred on a semiconductor substrate;

forming a first layer of a capping coating on the layer to betransferred, said first layer provides adhesion and protection fromoxidation;

forming a second layer of a capping coating on said first layer, saidsecond layer provides additional protection and adhesion to a carrierassembly;

adhering the carrier assembly to a carrier wafer by means of anadhesive; and

removing the semiconductor substrate whereby said layer to betransferred is attached to the carrier assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a prior art structure includinga single-layer capping coating.

FIG. 2 is a schematic representation of a structure of the presentinvention including a bi-layer capping coating.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to a method for manufacturing 3Dintegrated structures based on an assembly approach in which alayer-to-be transferred is coated with a bi-layer capping stack, apolyimide layer, and an adhesive layer. That structure is then bonded toa glass carrier-wafer and upon removal of the bulk silicon, it istransferred to a new circuit, and attached to this new circuit usingbonding techniques such as, for example, adhesive bonding. In thesubsequent step, the glass layer is released (for example, by laserablation), and the residual polyimide layer is removed by plasma ashingusing oxygen.

The aforementioned protecting capping stack is comprised of two layersincluding a first layer of silicon nitride and a second layer of anamino silane deposited over the whole area of the wafer. Such a bi-layercap provides not only protection from both Cu and oxygen diffusion, butit presents a SiCMOS-compatible and reliable solution for use in the 3Dapplications where Cu-polyimide layers are present. The thickness of thefirst and second layers of the inventive bi-layer capping coating mayvary depending on the conditions used for depositing each of the layers.Typically, the SiN layer has a thickness of from about 100 to about 1000nm, while the amino silane has a thickness of a few monolayers. Otherthickness besides the ranges mentioned herein are also contemplatedherein

The term “amino silane” is used in the present invention to denote acompound that has the formula:

wherein R₁, R₂, R₃, R₅, and R₆, independently of each other, can behydrogen or an organic radical such as, for example, a lower alkylradical containing from 1 to about 6 carbon atoms, an acyl radicalcontaining 1 to 6 carbon atoms, or an allyl, alkenyl or alkynyl radicalcontaining 2 to 6 carbon atoms and R₄ can be an organic radical such as,for example, a lower alkyl containing from 1 to about 6 carbon atoms oran aromatic system such as, for example, phenyl or benzyl derivative.Illustrative examples of amino silanes that can be employed in thepresent invention as the second layer of the bi-layer capping coatinginclude, but are not limited to: 3-aminopropyl-trimethoxy silane, vinylaminomethyl triacetoxysilane, and the like. Of the aforementioned aminosilanes, it is highly preferred to use 3-aminopropyl-trimethoxy silaneas the second layer of the bi-layer capping coating of the presentinvention.

As stated above, the first layer of inventive bi-layer capping coatingis a silicon nitride layer. The process of depositing silicon nitride iswell known. Illustrative methods that can be used in the presentinvention to deposit the silicon nitride layer of the bi-layer cappingcoating include, for example, spin-coating, chemical vapor deposition(CVD), plasma enhanced chemical vapor deposition (PECVD), chemicalsolution deposition, atomic layer deposition, evaporation, physicalvapor deposition (PVP), and other like deposition processes.

The silicon nitride layer of the bi-layer capping coating of the presentinvention exhibits good adhesion properties to materials used in theback-end-of the-line (BEOL) processing, namely conductive materials suchas Cu, and dielectric films including, for example, silicon dioxide,oxide films containing phosphorus or boron, such as phosphorus dopedsilicate glass (PSG), boron doped silicate glass (BSG), andboron-phosphorus doped silicate glass (BPSG), a silicon oxynitride,nitrides, and other low-k organic and non-organic films. Also siliconnitride allows for good chemical mechanical polishing (CMP) processselectivity to the aforementioned materials. Therefore, in Cu-dualdamascene structures, it is used as a CMP hard mask.

The above characteristics of silicon nitride allow this insulatingmaterial to be utilized as a capping layer in applications in whichmetal capping layers failed. Namely, silicon nitride can be depositedover the surface of the to-be-transferred layer (with Cu patternedstructure) followed by the amino silane deposition (formation of thebi-layer cap). Subsequently, the layer transfer steps are implemented(deposition of polyimide adhesives, attachment of glass, removal of thebulk silicon, bonding to a new substrate, release of glass carrier,strip of polyimide).

In embodiments wherein the silicon nitride is deposited over aninterconnect structure containing Cu metallurgy, the silicon nitrideserves as a Cu protection layer, preventing Cu oxidation. Depending onthe processing scheme, the silicon nitride layer can be easily removedby well-known wet or dry etching processes, or simply (and preferably)by a CMP process. In such a scheme, silicon nitride would serve as asacrificial layer. For other 3D applications, the silicon nitride layercan be left on as a constituent of the structure, and it can be, forexample, used as a passivation layer or as an etch stop layer to addadditional wiring layers.

In this invention, the bi-layer capping layer is proposed forCMOS-compatible processes related to 3D integration applications, henceit is expected that the thermal budget will not exceed 400° C. Thethermal stability of silicon nitride has been well documented for suchapplications. On the other hand, thermal stability of the aminosilane/polyimide system depends on the processing ambient. Thedegradation under nitrogen is minimal at 400° C. (16 hours), but airenriched nitrogen probably causes oxidation and decomposition ofunreacted surface amino silane.

However, the application of present invention is related to polyimidematerials which have to be cured in an oxygen-free ambient. Hence,without any added restrictions the stability of the aminosilane-polyimide interface is insured. All of the above informationleads to the conclusion that silicon nitride/amino silane system is anexcellent capping bi-layer for 3D integration applications whenCu-polyimide interfaces are involved.

The prior art structure of the assembly approach technique used in 3Dintegration applications is shown in FIG. 1. The structure consists of:a layered structure-to-be transferred 100, which includes bulk silicon101 and device layer 102 terminated by the Cu patterned wiring level103; capping layer 200; sacrificial polyimide layer 300; adhesion layer400; and glass carrier 500. In such a structure, only an amino silane,such as 3-aminopropyl-trimethoxy silane, is used as the capping layer200.

Amino silanes serve as adhesion promoters for patterned Si BEOLstructures enabling increased strength in the Cu-polyimide anddielectric-polyimide interfaces. In addition, amino silanes serve as Cudiffusion barriers, limiting the creation of Cu-containing precipitatesin the polyimide. However, upon plasma exposure the amino silane reducessimply to a layer of silicon oxide and electrical evaluation of thelayer transfer process using this scheme showed increased Cu wireresistivity. Hence, it has been concluded that Cu surface degradedduring the oxygen-plasma removal of the polyimide, caused by oxidationwas not prevented by the silicon oxide layer resulting from the oxidizedamino silane.

The present invention is based on a bi-layer approach, i.e., theprevious single capping layer 200 in this scheme is substituted by acapping layer 200′ which is comprised of two films: silicon nitride 201′underneath the amino silane layer 202′. The schematic diagram of theinventive structure is shown, for example, in FIG. 2. The combinedproperties of the silicon nitride 201′ (oxygen diffusion barrier layerwith good adhesion properties to BEOL materials), and amino silane layer202′ (adhesion promoter to polyimide) provides superior capping layercharacteristics.

In FIG. 2, reference numeral 100 denotes a layered substrate to betransferred. The layered substrate 100 includes a semiconductorsubstrate 100, device layer 102 which can be terminated with a layer 103that comprises at least one metallic element such as Ti, Ta, Zr, Hf,silicides, nitrides and conducting siliconnitrides of the aforementionedelemental metals; Cu, W, Al, composites of these metals with glass; andany combination thereof. Preferably, layer 103 comprises Cu. Themetallic element of layer 103 may be patterned, i.e., a patterned wiringlevel, or a blanket layer. When a patterned metallic element is present,portions of layer 103 may be comprised of an insulating materialincluding oxides, nitrides, oxynitrides, polymeric dielectrics andinorganic dielectrics. The insulating material may be porous ornon-porous. The layered substrate 100 is fabricated using any well-knownsemiconductor processing technique.

The semiconductor substrate 101 may be a bulk semiconductor including,for example, Si, SiGe, SiC, SiGeC, GaAs, InP, InAs and other III-Vcompound semiconductors, II-V compound semiconductors, or layeredsemiconductors such as silicon-on-insulators (SOI), SiC-on-insulator(SiCOI) or silicon germanium-on-insulators (SGOI). When the layeredsemiconductors are employed, the top layer of those substrates representthe device layer 102.

FIG. 2 also shows an example of a carrier assembly that can be employedin the present invention. The carrier assembly may include a carrierwafer 500, adhesion layer 400 and intermediate layer 300. The carrierassembly is fabricated using techniques that are well-known in the art.For example, the carrier assembly can be formed by applying an adhesivecoating atop a carrier wafer using a conventional deposition processsuch as spin-on coating, PECVD, CVD or physical vapor deposition (PVP).The intermediate layer is then applied by using one of the abovementioned deposition processes. In a preferred embodiment, the carrierassembly comprises glass and an intermediate layer of a polyimide.

Carrier wafer 500 may be comprised of a semiconductor including anygroup III-V or II-V semiconductor, SOI, SGOI, alumina, ceramics and thelike. Intermediate layer 300 of the carrier assembly is any polyimidematerial, which is typically used as an adhesive coating in such astructure. Examples of polyimide materials that can be employed in thepresent invention include polyamic acid (PAA)-based polyimides, polyimicester-based polyimides and pre-imidized polyimides.

Adhesion layer 400 includes coupling agents such as amino silanes.Adhesion layer 400 serves to bond the carrier wafer 500 to theintermediate layer 300.

The 3D structures transferred using this bi-layer (silicon nitride/aminosilane) approach preserved circuit performance, indicating that theinventive bi-layer capping coating reliably performs its function.

This invention is based on the use of the wafer-level layer transferprocess which incorporates the inventive bi-layer capping coatingdescribed above. This type of passivation material is proposed since itis compatible with current CMOS technology. Specifically, thewafer-level layer transfer method of the present invention includesfirst providing a layer to be transferred on a semiconductor substrateusing well known CMOS process steps. The first layer of the inventivecapping coating, e.g., silicon nitride, which provides good adhesion andprotection from oxidation for the layer to be transferred is then formedusing a conventional deposition process such as spin on coating, PECVD,CVD or PVP. Next, the second layer of the inventive capping coating,i.e., the amino silane, which serves as an additional diffusion barrierand provides adhesion to the carrier assembly is applied to the firstlayer using spin on coating, PECVD, CVD or PVP. The carrier assemblycomprising the intermediate layer attached to a carrier wafer by meansof suitable adhesive is then adhered to the second layer. After thisstep, the semiconductor substrate is removed such that the layer to betransferred is attached to the carrier assembly thus achieving layertransfer. The removal may be achieved by laser ablation or etching.

The method of the present invention may further comprise the steps ofjoining an exposed surface of the transferred layer to a top surface ofa receiver substrate, and removing the carrier assembly to achievefurther transfer of the transferred layer from the carrier assembly tothe receiver substrate.

In this embodiment, the semiconductor and receiver substrates containsemiconductor components and the carrier assembly is used to enable thelayer transfer of the semiconductor components from semiconductorsubstrate onto semiconductor components from the receiver substrate.

The focus of this invention is on ability to integrate multifunctional3D structures with active and passive components by coating theirinterconnecting elements with passivation layer to protect them fromdegradation during the layer transfer process.

The concepts disclosed in the present invention can be used to addfunctionality to the 3D ICs without deviating from the spirit of theinvention. For example, the methods can be applied to futureoptoelectronic device structures. In such cases, firstly the type of thematerial to create the layers can be replaced by other materials such asII-VI and III-V materials, (example: gallium arsenide or indiumphosphide) and organic materials, and should be selected according tothe specific application however similar bi-layer passivation can beused to preserve electrical and mechanical stability of thesemiconductor elements. Secondly the functional bi-layer can be anintegral part of an optoelectronic structure, including future3-dimensional circuit stacks, allowing for integration of complexmultifunctional and mixed-technology systems or elements on a singlewafer.

While the present invention has been particularly shown and describedwith respect to preferred embodiments, it will be understood by thoseskilled in the art that the foregoing and other changes in forms anddetails may be made without departing from the spirit and scope of thepresent invention. It is therefore intended that the present inventionnot be limited to the exact forms and details described and illustrates,but fall within the scope of the appended claims.

What is claimed is:
 1. A method of constructing a structure for interconnecting semiconductor components, comprising: forming a bi-layer capping coating on the substrate, the bi-layer capping coating comprising a nitride-containing layer on the substrate and an amino silane layer on the nitride-containing layer, each layer of said bi-layer capping coating providing protection and adhesion, wherein said nitride-containing layer protects the metallic element from an oxygen-based plasma removal process; and forming a carrier assembly on the capping coating.
 2. The method of claim 1 wherein said carrier assembly is formed by: applying an adhesive coating on a top of a carrier wafer; and depositing an intermediate layer on the adhesive coating.
 3. The method of claim 1 wherein said capping coating is formed by depositing at least two consecutive layers and hence creating a bi-layer protecting said substrate to be transferred from negative effects of attachment and the later removal processes of said carrier assembly.
 4. The method of claim 1 wherein said bi-layer capping is formed by: forming a first layer of the bi-layer capping coating for providing a barrier to diffusion and adhesion to said substrate to be transferred; and forming a second layer of bi-layer capping coating for providing adhesion to said carrier assembly and providing further protection against diffusion.
 5. The method of claim 1 wherein bi-layer capping coating is formed by spin on coating, plasma enhanced deposition, physical or chemical vapor deposition.
 6. The method of claim 1, wherein the nitride-containing layer is silicon nitride.
 7. The method according to claim 2, wherein the material of said carrier wafer is selected from glass and quartz. 